1. Field of the Invention
The present invention relates to a level device, and more particularly to a level device which can define a circumferential leveling plane.
2. Description of the Related Art
Nowadays, during the course of carrying out a construction project, especially when decorating the outside or inside walls of the construction, it's very difficult to mark a horizontal plane on different walls. One method is to adopt rulers to draw a horizontal line on the walls roughly, but, this kind of method is slow and not accurate, and can't ensure the quality thereof. Another method is to make use of press relation of a long thin pipe with liquid contained therein to mark a common horizontal plane on the different walls. But, this method is not convenient for application in large work site. Hence, levels which can mark a horizontal line are introduced.
According to the output modes of the light, the current leveling device is divided into two types, directly-output type and rotatably-output type. The level of directly-output mode disperses light beams from a laser device to reach a larger angle and form a parallel output along a horizontal direction by means of a cylindrical lens. This kind of level has a disadvantage that the angel of the output is limited. That is to say, the length of the leveling line on the target body marked by the level is limited. When a long or circumference mark is needed in a special circumstance, it is necessary to mark many times or to assemble several optical lens systems together so as to realize its function. The two methods provided above are inconvenient, or complicate the assembled device.
The level of the rotatably-output type rotates the point light laser source with high speed to produce a horizontal light fan-shaped plane, due to the characteristics of vision temporary stay, and to define a horizontal reference mark on the target surface. This kind level overcomes the disadvantage of marking limitation in length and angle, however, the precision of the leveling device is affect because of vibrating of the rotatable mechanism. Furthermore, this kind levels needs power to support the rotation of the mechanism.
Hence, an improved level which can define a circumference mark and is simple in configuration and low in cost is desired to overcome the above shortcomings.